During the last five years, there has developed a body of literature and a group of investigators concerned with a variety of chromosomal abnormalities in cultured animal cells and in human tumors. These abnormalities include the presence of extra-chromosomal elements called double minute chromosomes, as well as expanded regions of chromosomes called homogeneously-staining regions. Other investigators have been studying mechanisms of resistance to various agents that kill cells, such as cancer chemotherapeutic agents. They have found that, in certain instances, the mechanism of resistance involves the selected amplification of specific genes. The amplified genes are present in homogeneously-staining regions of chromosomes, or occur on double minute chromosomes. Thus, these two different areas of investigation, chromosomal abnormalities and drug resistance, have focused on the same general phenomenon. The proposed conference is intended to bring together persons studying various aspects of gene amplification with persons studying chromosome aberrations. A group of this type has not met previously. It is now appropriate to have a small meeting to share results and concepts. The individuals to be invited come form diverse fields, all related to gene amplification and chromosome structure. They include workers in bacterial genetics and DNA replication students of drug resistance per se as well as persons concerned with the structure and function of chromosomes. The list includes basic scientists as well as researchers studying chromosome structures in malignancy. The conference is scheduled for 20 to 23 September 198l, at the Banbury Center of Cold Soring Harbor Laboratory. The meeting will provide time not only for formal presentations but also for discussion and informal interactions.